$\"\"$ $\"\"$

The expression is $\"\"$

Whether the equation is true or not

$\"\"$

$\"\"$ (Product of two same signs is positive)

According to Subtraction Property of equality: If $\"\"$ then, $\"\"$ .

$\"\"$ (Subtract 72 from each side)

$\"\"$ (Additive inverse property: $\"\"$ ) $\"\"$

$\"\"$ (Additive identity property: $\"\"$ )

$\"\"$ (Divide each side by 9)

$\"\"$ (Cancel common terms)

$\"\"$ (Divide: $\"\"$ ) $\"\"$

The equation is true.